Pushbutton switch assembly with interlock structure

ABSTRACT

A pushbutton module has the latch bar mounted in the module by molded-in formations and by interengagement with the pushbutton, instead of being held in position by separate members. Also the pushbuttons have formations which interengage with a formation on a part of the telephone set to maintain the pushbuttons in assembled position. The switch module is simplified and the number of parts decreased.

United States Patent Kuhlus [451 Sept. 23, 1975 PUSHBUTTON SWITCH ASSEMBLY WITH INTERLOCK STRUCTURE Gerd Kuhius, London, Canada Northern Electric Company Limited, Montreal, Canada Filed: July 17, 1974 Appl. No.: 489,174

Inventor:

Assignee:

US. Cl. 200/5 EA; 200/50 C; ZOO/328; 74/483 PB Int. Cl. HOIH 9/24 Field of Search 200/5, 50 C, 314, 328; 74/483 PB References Cited UNITED STATES PATENTS 9/1966 Wirsching 200/5 EA 3,517,140 6/1970 Bailey et al. 200/5 E Primary ExaminerJames R. Scott Attorney, Agent, or Firm-Sidney T. Jelly [57] ABSTRACT A pushbutton module has the latch bar mounted in the module by molded-in formations and by interengagement with the pushbutton, instead of being held in position by separate members. Also the pushbuttons have formations which interengage with a formation on a part of the telephone set to maintain the pushbuttons in assembled position. The switch module is simplified and the number of parts decreased.

3 Claims, 3 Drawing Figures Sheet 1 of 2 Sept. 23,1975

'1 US Patent US Patent Sept. 23,1975 Sheet 2 of2 3,908,101

PUSI'IBU'ITON SWITCH ASSEMBLY WITH INTERLOCK STRUCTURE This invention relates to pushbuttonkey modules for telephones. 1

Pushbutton switches are usedin numerous forms of telephone sets. A conventional module comprises a plurality of pushbutton switches, together with a latch bar which holds one pushbutton in;an operated position, and also lock-out devices to prevent more than one pushbutton being moved to an actuating position simultaneously. A release button is also usually provided. v 'i In the conventional module, the pushbuttons are held in the module by a separate frame member-usually of metal. Similarly, the latch bar andthe lock-out devices are held assembled to the main body memberof the module by the frame member. The frame member is usually used also to attach the module tolthe telephone set housing. I I 7 if j v v The present invention provides a pushbutton module in which the latch baris mounted in the moduleand is retained inthe module by molded-informations andby interengagement with the pushbuttons. The pushbuttons are provided with formations which interengage with a formation on part of the telephone set, when the module is installed, to maintain the buttons in position in the module. The switch moduleis simplified and the number of parts decreased.

The invention will be readily understood by the following description of one embodiment, by way of ex ample only, in conjunction with' the accompanying drawings, in which:

F IG. 1 is a perspective view of a module in exploded form together with a part of the telephone set to which it is attached;

FIG. 2 is a plan view of the main body portion of the module with the latch bar in position; and

FIG. 3 is a cross-section on the line III-III of FIG. 2, with a pushbutton in position.

Illustrated in FIG. 1 is a pushbutton switch module having three pushbutton switches. The module is illustrated in exploded form, with one detail repeated in a larger scale for clarity. The main body of the module is at 10. The module is of molded plastics material of channellike formation, and has an end flange 11 at each end and three hollow guide members 12. A front web 13 has various formations molded therein or thereon as will be described. End flanges 11 and front web 13 are formed in one unit with a base web 14. The

hollow guide members 12 extend upwards from the base web 14.

On the face of the front web 13, near the bottom edge thereof, is a channel formation 15. The channel formation provides a groove 16 in which can slide a latch bar, as to be described. At each end of the face of the front web 13, at the top edge thereof, two projec tions 17 each have a groove 18 facing toward the groove 16. Opposite each guide member 12 the front web has a U shaped aperture 19, open at the top. A short projection 20 on one end flange 11 provides a spring abutment.

Three springs fit over the three guide members 12, a spring on each guide member. A hollow pushbutton 26 fits over each guide member 12, each pushbutton having a bottom surface which rests on the spring 25. Not seen in FIG. 1, but shown in FIG. 3 and described later, are projections or abutment members on the back surfaces of the pushbuttons 26. These engage under-a projecting rib on the supporting part or member to which the module is attached. In the present example the member to which the module is attached is a metal casting 27. The projecting rib is seen at 28.

r A latch bar is seen at 29. In the example considered, the latch bar has a base part 30 and three projections 31, 32 and '33. The projections are spaced and positioned so as to be opposite pushbuttons when assembled.-Two projections 31 and 32 have an upward facing inclined surface 34'and an undercut surface 35. The third projection 33, has a downward facing inclined surface 56.At one end of the base part 30 is a stub 37. A compression spring 38 is'fitted over this stub and abuts against the projection 20 on end flange 1-1.

To assemble and attach the pushbutton module, the springs 25 are put over the guides 12, the latch bar 30 is slid into the grooves 16 and 18, with the spring 37 against the stop or abutment 20. The pushbuttons 26 are pushed'dow'n'on the guides 12. While the buttons 26 are held down themodule is positioned in the angled recess 39 in the member 27. The end flanges 11 are pushed up against two projections 40 and 41 on the member 27 and screws inserted through holes 42 into the end flanges 1 1.

Each pushbutton 26'is provided with a small projection'45 to which can be attached a member which coacts with th'elatching bar 29. In the example illustrated the centre pushbutton 26 has a short projecting pin 46. When this pushbutton is pushed downthe pin 46 acts on the related upward facing inclined surface 34, 'sliding the latch'bar sideways -to the right of FIG. 1. The pin eventually proceeds'down and the latch bar can slide back. The pin in then trapped by the undercut surface 35. This holds the pushbutton in an activated position. The right hand end pushbutton 45, in FIG. 1, has a release member 47 attached to its projection 45, the member 47 having a small projection 48. The release member 47 is of a springy material and on pushing down the end pushbutton the release member deflects or bends slightly and passes down behind the latch bar 29. Having passed completely behind the latch bar 29, the small projection 48 projects below the downward facing inclined surface 36. On release of the pushbutton, this projection 48 of the release member 47 engages with the surface 36 and slides the latch bar sideways -to the right in FIG. 1. The form of the release member 47 is seen in more detail, to a larger scale in the circle X, FIG. 1. The sideways movement releases the pin 46 of centre pushbutton 26, then pushbutton returns to an inoperative or non-activated position. The third pushbutton 26, the left-hand pushbutton in FIG. 1 is shown without any member attached to the projection 45. Thus this pushbutton will simple move up and down under finger pressure without any latching. Alternatively a pin can be provided for this button as for the centre button. In such an arrangement, pushing down a first button with a pin, for example, the centre button, results in its being latched. Pushing down the second button with a pin will cause release of the first button and latching of the second. The third button will release either of the other buttons. The release member 47 is shown to a larger scale alongside the related button in FIG. 1.

FIGS. 2 and 3 illustrate the form of a module. Particularly in FIG. 3 is seen the mounting of the latch bar 29,

the pushbutton 26 and an abutment member 50 on the rear of the pushbutton. There are two abutment members 60 on each button in the particular example. As previously described, the abutment members 50 engage under the projecting rib 28 of the casting 27, seen in FIG. 1 and limit upward movement of the pushbuttons. The abutment members 50 also actuate switch contacts, indicated in dotted outline at 51. The contacts 51 are positioned in slots formed in the base web 14 and are also positioned by projections 52 along the back edge of the base web. The number, and disposition, of contacts can be varied in accordance with the particular switching requirements. Wires 53 are included in FIG. 1, and these wires are soldered to the ends of the contacts 51 as seen in FIG. 3.

What is claimed is:

1. In a pushbutton module comprising a molded body portion; a latch bar supported in slideable relation to a face on the body portion; a plurality of pushbuttons resiliently mounted on said body portion; projections on at least two of said pushbuttons and projecting from said face on said body portion; a formation on said latch bar opposite each projection on a pushbutton; at least one pushbutton projection and the related formation interengaging such that actuation of said pushbutton engages the pushbutton projection with the related formation to slide said latch bar from an initial position, the pushbutton formation moving past said formation to permit sliding of said latch bar back to said initial position, said formation engaging with the related pushbutton projection to latch said pushbutton in its actuated position; a further one of said pushbutton projections including a resilient member, said resilient member deflecting and moving past the related formation on said latch bar on actuation of the related pushbutton, release of the pushbutton engaging said resilient member with the related formation to slide said latch bar from the said initial position to release any latched pushbutton, said latch bar slideable to said initial position on release of said resilient member from the related formation on final release of the related pushbutton; and resilient means urging said latch bar to said initial position, the improvement comprising a channel formation formed in an upper surface of an integral projection at a lower part of said face; integral projections at an upper part of said face, and a groove in each integral projection, the grooves in opposition to said channel formation, said latch bar slideably supported at a bottom edge in said channel formation at a top edge in said grooves, said latch bar retained in said slideable relation to said face on said body portion by said channel formation and said grooves.

2. In a pushbutton module as claimed in claim 1 at least one abutment member on each pushbutton; switch contacts on said body portion, said abutment members actuating said switch contacts on actuation of a related pushbutton.

3. In a pushbutton module as claimed in claim 2 including a support member, means attaching said body portion to said support member and a formation on said support member for engagement with said abutment member on each pushbutton, engagement of said abutment member with said formation on said support member locating each pushbutton in a non-actuated position. 

1. In a pushbutton module comprising a molded body portion; a latch bar supported in slideable relation to a face on the body portion; a plurality of pushbuttons resiliently mounted on said body portion; projections on at least two of said pushbuttons and projecting from said face on said body portion; a formation on said latch bar opposite each projection on a pushbutton; at least one pushbutton projection and the related formation interengaging such that actuation of said pushbutton engages the pushbutton projection with the related formation to slide said latch bar from an initial position, the pushbutton formation moving past said formation to permit sliding of said latch bar back to said initial position, said formation engaging with the related pushbutton projection to latch said pushbutton in its actuated position; a further one of said pushbutton projections including a resilient member, said resilient member deflecting and moving past the related formation on said latch bar on actuation of the related pushbutton, release of the pushbutton engaging said resilient member with the related formation to slide said latch bar from the said initial position to release any latched pushbutton, said latch bar slideable to said initial position on release of said resilient member from the related formation on final release of the related pushbutton; and resilient means urging said latch bar to said initial position, the improvement comprising a channel formation formed in an upper surface of an integral projection at a lower part of said face; integral projections at an upper part of said face, and a groove in each integral projection, the grooves in opposition to said channel formation, said latch bar slideably supported at a bottom edge in said channel formation at a top edge in said grooves, said latch bar retained in said slideable relation to said face on said body portion by said channel formation and said grooves.
 2. In a pushbutton module as claimed in claim 1 at least one abutment member on each pushbutton; switch contacts on said body portion, said abutment members actuating said switch contacts on actuation of a related pushbutton.
 3. In a pushbutton module as claimed in claim 2 including a support member, means attaching said body portion to said support member and a formation on said support member for engagement with said abutment member on each pushbutton, engagement of said abutment member with said formation on said support member locating each pushbutton in a non-actuated position. 